1. Field of Invention
This invention relates generally to the disposal of poison gases of the type used in chemical warfare, and more particularly to a technique in which the poison gas to be treated is conducted through a bath of anhydrous liquid hydrogen chloride to render it innocuous.
2. Status of Prior Art
The first effective use of poison gas in chemical warfare took place in World War I when the Germans released chlorine gas against the Allies on the Western Front. Later, in the same war, the Germans introduced mustard gas.
Afterwards the major powers continued to stockpile poison gases for possible future use. Actual use of poison gas was made by the British in Afghanistan and by the French and Spanish in Africa. But during World War II lethal gases were not employed except by the Germans in concentration camps. However, lethal chemical gases are being stockpiled by many nations and in some instances are put to actual use. Thus mustard gas was used by Iraq during its war with Iran and also against Kurdish rebels.
Poison gases are roughly grouped according to their port of entry into the body and their physiological effects. Thus Lewisite like mustard gas, is a blistering agent which penetrates the skin and has fatal consequences. Nerve gases inhibit proper nerve function, while lung irritants attack the respiratory tract and cause pulmonary edema.
In 1990 at the end of the cold war, the U.S. and the USSR agreed to discontinue the production of poison gases and to sharply reduce their existing arsenal of these gases. The purpose of this agreement was to create a climate of change discouraging smaller nations from stockpiling such lethal weapons.
The concern of the present invention is with a technique usable with existing stockpiles of poison gases to render these gases innocuous. The need to detoxify existing stockpiles of poison gas is becoming increasingly urgent, for aging containers and facilities for storing these gases cannot survive the ravages of time and corrosion.
The several known chemical warfare gases, their chemical names, their mode of action and short-term and long-term toxic effects are set forth in the article "Disposing of the U.S. Chemical Weapons Stockpile" by Carnes and Watson in the JAMA Journal of August 1989 (Vo. 262, No.5).
Toxic compounds, such as Sarin, Mustard gas, VX and GB can be destroyed by pyrolysis or incineration. But in doing so there is a serious risk of producing toxic effluents. In a technique in accordance with the invention, these toxic gases are rendered innocuous by degradation in a reaction chamber filled with an anhydrous liquid halide without however producing toxic by-products.
My prior U.S. Pat. Nos. 4,235,968 and 4,260,685 disclose an auto-reaction utilizing feedstock cellulosic material and liquid anhydrous hydrogen chloride. The liquid anhydrous hydrogen chloride functions as a catalyst for the hydrolysis of the glycosidic bonds within the cellulose. The over-abundance of catalyst promotes this reaction even in the absence of free water molecules. The water for hydrolysis is donated by the cellulose. Hydrogen and hydroxy radicals are torn from the carbonaceous cellulose backbone and interposed between the oxygens of the glycosidic bonds. This reaction should not be confused with the established acid hydrolysis methods. The absence of free water and the over-abundance of halide catalyst make the chemistry quite distinct. EQU R--C--CH--CH--O--O--CH--CH--C--R converts to R--C--CH--CH--OH +HOO--CH--CH--C--R
This reaction takes place under very mild conditions. The conditions for this reaction may be altered by raising the temperature to ambient conditions, thereby causing the hetero oxygen bonds in the ring glucose units to also degrade. In summary this reaction causes almost all carbon-hetero-carbon and carbon-hetero-hetero bonds to rupture with the formation of hydroxyl, carboxylic, anhydride and similar side chains. We have found that these basic reactions can result in the degradation of certain highly toxic compounds such as VX, GB, Sarin and Mustard gas. The kinetics of these reactions are such that even molecules that might resist and reform during high temperature pyrolysis (incineration) will undergo rearrangement upon contact with the liquid halides. Also the sealed nature of the reaction vessel, to maintain pressure and the liquid state of the reactants, permits a continuous process in which as the toxic gases percolating through a bath of liquid anhydrous hydrogen chloride emerge as benign by-product components.